code: def test_resampler_3d_symmetric_cubic_correctness(self):
      test_grid = tf.constant(
          [
              [[-0.25, -0.25, -0.25], [0.25 + 2, 0.75 + 2, 0.25 + 4]],
              [[0.75, 0.25, -0.25 + 4], [0.25, 0.25, 0.75]],
          ],
          dtype=tf.float32,
      )
      expected = [
          [[3.683675], [4.140218]],
          [[12.56551075], [10.69881153]],
      ]
      self._test_correctness(
          input=self.get_3d_input1(),
          grid=test_grid,
          interpolation="BSPLINE",
          boundary="SYMMETRIC",
          expected_value=expected,
      )
  
imports: from __future__ import absolute_import, print_function, division
  import numpy
  import tensorflow
  import tensorflow.test
  from niftynet.contrib.layer.resampler_optional_niftyreg import ResamplerOptionalNiftyRegLayer
  from tests.niftynet_testcase import NiftyNetTestCase
  import niftynet.contrib.layer.resampler_optional_niftyreg
label_desc: Use image node_id 12 for calling the ResamplerTest obj's underlying member method code with example usage: obj.test_resampler_3d_symmetric_cubic_correctness() without return types